Ptolemy pronunciation

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Ptolemy birth and death
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Ptolemy

Roman astronomer and geographer (c. 100–170)

For other uses, see Ptolemy (disambiguation).

Claudius Ptolemy (; Ancient Greek: Πτολεμαῖος, Ptolemaios; Latin: Claudius Ptolemaeus; c. 100 – 160s/170s AD)^[1] was an Alexandrian mathematician, astronomer, astrologer, geographer, and music theorist^[2] who wrote about a dozen scientific treatises, three of which were important to later Byzantine, Islamic, and Western European science. The first was his astronomical treatise now known as the Almagest, originally entitled Mathematical Treatise (Greek: Μαθηματικὴ Σύνταξις, Mathēmatikḗ Syntaxis). The second is the Geography, which is a thorough discussion on maps and the geographic knowledge of the Greco-Roman world. The third is the astrological treatise in which he attempted to adapt horoscopic astrology to the Aristoteliannatural philosophy of his day. This is sometimes known as the Apotelesmatika (Greek: Αποτελεσματικά, lit. 'On the Effects') but more commonly known as the Tetrábiblos, from the Koine Greek meaning "Four Book

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Ptolemy, a Greek astronomer and geographer, lived in around 85 to 165 A.D. He was born in Egypt, and he died there too. Egypt was the center of learning in those times, and it was there that Ptolemy got his education. His name Ptolemy is, in fact, an Egyptian name, while Claudius is a Roman name. This indicates that he belonged to a Greek family that lived in Egypt and that had been bestowed the honor of being a Roman citizen, an honor that was likely conferred by the Roman emperor himself.

Ptolemy wrote down his work in a long, thirteen-book treatise called the Almagest. This compilation was considered very important and influential to other mathematicians and scientists in those early times. It was translated into Arabic and then Latin, and made accessible to many people. For present-day students, it presented an exact account of Ptolemy’s discoveries and contributions to science.

In the Almagest, Ptolemy wrote of his mathematical studies regarding the motions of the planets, the sun and the moon. He presented the so-called geocentric theory, which stated that the ea

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Claudius’ finished his first major work on astronomy was he was 50 years old. It was based on the observations he had made over the previous 20 to 30 years. He called his book, The Almagest, which meant ‘The Greatest’. In his work, Claudius described the movements of objects in the night sky using maths. He believed the paths of the stars and planets were not random. He explained them by combining several circular movements.

In Claudius' model of the Solar System, the Earth was stationary. It was surrounded by a great sphere which carried the stars, planets, Sun and Moon around the Earth. This idea of a geocentric (Earth centred) Solar System became known as the Ptolemaic system.

The Almagest also contains a star catalogue. It listed 48 constellations which could be seen from the Northern Hemisphere. Claudius' later work, ‘Planetary Hypotheses’ was more mathematical than The Almagest. It set out the Universe as a series of spheres and estimated the distances to the Sun and the 'fixed stars'.